In obese children, blood lipid levels, insulin levels, and blood pressure have been associated with measures of obesity. In addition, a central versus peripheral pattern of body fat distribution has also been positively correlated with these cardiovascular disease risk factors. Furthermore, liver function abnormalities potentially related to fatty infiltrate of the liver, have been described in obese individuals. However, the potential interaction between these factors has not been well described, especially in children. Abdominal fat has been associated with increased cardiovascular disease risk factors. The best measure of abdominal fat has utilized computerized tomography or magnetic resonance imaging. However, due to the expense and other factors, CT and MRI are not practical for broad utilization. Dual x-ray absorptometry has been shown to accurately assess body composition, and preliminary information suggests that regional fat distribution (e.g. abdominal fat) can be accurately assessed using this technology. However, no information exists relating to the utility of DEXA in accessing regional fat distribution in morbidly obese children. The speed, ease of completion, and minimal radiation exposure would make DEXA a very practical research and clinical assessment instrument, should it be shown to be accurate. This study has been designed to examine the utility of utilizing dual x-ray absorptometry to evaluate abdominal fat in morbidly obese children. In addition, it will be used to gather preliminary information relating to relative weight, body composition, body fat distribution, leptin levels, cardiovascular disease risk factors, and liver function abnormalities in morbidly obese children. This information will be used as pilot data to develop future full research protocols to monitor body composition, regional fat distribution and cardiovascular disease risk factors for obese children participating in weight management programs.